1. Field of the Invention:
The present invention relates to a still picture transmitting and receiving system for transmitting video signal information such as a TV signal via a telephone line and the like.
2. Description of the Related Art:
Quite recently, a system has been devised according to which a TV signal is transmitted by making use of a telephone line or the like and is printed on a light sensitive paper or by a video printer or the like. FIG. 1 shows the system as a whole.
1 is a rotating magnetic sheet, and 2 is a motor for driving the sheet 1. A reproducing head 3 is arranged on the rotating magnetic sheet 1 to reproduce a still picture for one field or frame. The reproduced signal is inputted in a reproduced video processing circuit 4 to be converted into a form such as of an NTSC signal or a line sequential signal. This video signal is displayed by a monitor 5 and at the same time inputted into an RGB matrix 6. In the RGB matrix 6, the reproduced video signal is matrix-processed to obtain each component of R, G, B. Further, these signal components are processed with a complementary color conversion, a .gamma.-correction, masking and so on at a video signal processing circuit 7.
An output of the video signal processing circuit 7 is converted into a digital value by an A/D converter 8, and quantized into, for example, 8 bits, namely the level of 256 steps. The respective data of Yl, Mg, Cy are stored in a frame memory 9 in sequence by every operation to be explained later, and are read out according to a transmitting rate of a transmission line K. At this time, the above data is added to a phase synchronizing signal at a transmitted signal forming circuit 10 so that a printing at the receiving side can be carried out at the same timing.
11 constitutes a transmitter, whose output is transmitted to the receiver via the transmission line K.
At the receiving side, the transmitted data is once stored in a frame memory 12, sequentially D/A converted by a D/A converter 13 into analog signals of Yl (yellow), Cy (cyan) and Mg (magenta), and displayed by a monitor 16 via an NTSC encoder 15. The signals are at the same time delivered to a printer 14. In the printer 14, each color component obtained from Yl, Cy, Mg signals serves to control, for example, the amount of ink in the case of an ink jet printer when a light sensitive material is exposed.
So far, in the case where color signals are to be transmitted, all three of Yl, Cy, Mg have been explained. However, in practice, at times an under-color is eliminated from the three complementary color signals to form a black print, and these color signals are transmitted, being newly added with Bk (black). Further, video signals nals reproduced especially from the magnetic sheet explained above are line sequential signals as the result of standardization, so that they are not a combination of three complementary colors or three complementary colors and one black print, but can assume other combinations. Further, not only in case where color video signals are transmitted but also in case where monochrome signals are transmitted, distinction between the transmitting rates such as for high speed or low speed might be necessary for the printer.
Until now, when such a distinction is needed, a transmitting mode is verbally communicated to the receiving side, for example, by telephone in advance of transmission, while at the receiving side a receiving state is manually set according to the transmitting mode communicated in advance. Therefore, the operation is complicated and inconvenient.
Further, in the case of a normal facsimile apparatus, a technique is that information of a transmitting mode is communicated to the receiving side in advance so as to automatically set the receiving side according to such transmitting mode. However, such technique is not known in an apparatus for transmitting and receiving a color video signal.